#!/bin/bash
# DISCLAIMER: 
# This script is provided "AS IS" and is intended solely for illustrative or educational purposes. 
# Domotz makes no warranties, express or implied, including but not limited to warranties of merchantability, fitness for a particular purpose, or non-infringement. Use of this script is at your own risk. 
# By using this script, you acknowledge and agree that Domotz shall not be liable for any direct, indirect, incidental, or consequential damages or losses arising from its use.  
# You further agree to indemnify, defend, and hold harmless Domotz and its affiliates from and against any claims, liabilities, damages, or expenses resulting from your use or misuse of this script. 
#
# In the event of any conflict between this disclaimer and any other agreement between you and Domotz, this disclaimer shall prevail with respect to the use of this script. 
#
# This script provides an example configuration for setting up Virtual LANs (VLANs) on a Linux system. 
# It demonstrates the creation of a VLAN interface with a specified VLAN ID on top of an existing network interface.
# Prerequisites:
# - the system should use the netplan file for network configuration.
ver="1.0"

# !!!Please changhe the path of the netplan file according to your system setup.!!!

# Change this to your netplan file path
NETPLAN_FILE="/etc/netplan/00-installer-config.yaml"

# Check if the script is run as root
if [[ $EUID -ne 0 ]]; then
    echo "This script must be run as root"
    exit 1
fi


# Function to check if the IP address is valid
validate_ip() {
    local ip_with_mask=$1
    local ip=${ip_with_mask%%/*}
    local mask=${ip_with_mask##*/}

    # Validate IP format
    if [[ $ip =~ ^([0-9]{1,3}\.){3}[0-9]{1,3}$ ]]; then
        IFS='.' read -r -a octets <<< "$ip"
        for octet in "${octets[@]}"; do
            if ((octet < 0 || octet > 255)); then
                return 1
            fi
        done
    else
        return 1
    fi

    # Validate subnet mask if present
    if [[ $ip_with_mask == */* ]]; then
        if ! [[ $mask =~ ^[0-9]{1,2}$ ]] || ((mask < 16 || mask > 32)); then
            return 1
        fi
    fi

    return 0
}

# Function to add /24 subnet mask if not provided
add_subnet_mask() {
    local ip=$1
    if [[ ! $ip =~ /[0-9]{1,2}$ ]]; then
        ip="${ip}/24"
    fi
    echo "$ip"
}

# Function to check if the input is a number
is_number() {
    local num=$1
    [[ $num =~ ^[0-9]+$ ]]
}

# Show the interfaces currently configured
echo "Current interfaces configuration:"
echo ""
ip -o link show | awk -F': ' '{print $2}' | grep -v lo
echo ""
echo "========================"

# Function to check if an interface exists
validate_interface() {
    local iface=$1
    ip -o link show | awk -F': ' '{print $2}' | grep -v lo | grep -wq "$iface"
}

# Function to get ordinal number in uppercase
get_ordinal() {
    local number=$1
    case $number in
        1) echo "FIRST";;
        2) echo "SECOND";;
        3) echo "THIRD";;
        4) echo "FOURTH";;
        5) echo "FIFTH";;
        6) echo "SIXTH";;
        7) echo "SEVENTH";;
        8) echo "EIGHTH";;
        9) echo "NINTH";;
        10) echo "TENTH";;
        *) echo "${number}TH";;
    esac
}

# Ask on which interface to configure the VLANs
while true; do
    read -p "Enter the interface name to configure VLANs: " IFACE
    if validate_interface "$IFACE"; then
        break
    else
        printf "Interface not found. Please enter a valid interface name.\n" >&2
    fi
done
echo "========================"

# Ask the number of VLANs to configure
while true; do
    read -p "Enter the number of VLANs you want to configure: " VLAN_COUNT
    if is_number "$VLAN_COUNT"; then
        break
    else
        printf "Invalid input. Please enter a numeric value.\n" >&2
    fi
done
echo "========================"

# Define a function to make backup with incrementing names
make_backup() {
    local file=$1
    local backup_dir; backup_dir=$(dirname "$file")
    local backup_name; backup_name=$(basename "$file")
    local i=1
    while [[ -f "$backup_dir/${backup_name}.bak$i" ]]; do
        let i++
    done
    cp "$file" "$backup_dir/${backup_name}.bak$i"
    echo "Backup made as ${backup_name}.bak$i"
}
echo "========================"

# Collect VLAN details
declare -A vlans
for (( i=1; i<=VLAN_COUNT; i++ )); do
    ordinal=$(get_ordinal $i)
    echo "Configuring the $ordinal VLAN of $VLAN_COUNT"
    
    while true; do
        read -p "Enter VLAN ID for the $ordinal VLAN: " vlan_id
        if is_number "$vlan_id"; then
            break
        else
            printf "Invalid input. Please enter a numeric value.\n" >&2
        fi
    done

    # Validate and get the IP address with subnet mask
    while true; do
        read -p "Enter IP (e.g., 192.168.1.1 or 192.168.1.1/24) for the $ordinal VLAN: " ip
        ip=$(add_subnet_mask "$ip")
        if validate_ip "$ip"; then
            break
        else
            printf "Invalid IP address or subnet mask wider than /16. Please enter a valid IP address.\n" >&2
        fi
    done

    vlans[$vlan_id]=$ip
    echo "VLAN ${IFACE}.${vlan_id} with IP $ip added"
    echo "========================"
done

# Recap
echo "Here's the summary of what you're about to apply:"
for id in "${!vlans[@]}"; do
    echo "Interface ${IFACE}.${id}, VLAN ID $id, IP ${vlans[$id]}"
done
echo "========================"

# Preview the netplan file with new configurations
echo "Preview of the netplan file with new configurations:"

# Read the existing netplan file, excluding any existing VLAN sections
if ! awk '
    /^  vlans:/ {delete_block=1}
    /^[^ ]/ {delete_block=0}
    !delete_block' "$NETPLAN_FILE" > "${NETPLAN_FILE}.tmp"; then
    printf "Error reading netplan file.\n" >&2
    exit 1
fi

# Append the new VLAN configurations
cat <<EOL >> "${NETPLAN_FILE}.tmp"
  vlans:
EOL

for id in "${!vlans[@]}"; do
    cat <<EOL >> "${NETPLAN_FILE}.tmp"
    ${IFACE}.${id}:
      id: ${id}
      link: ${IFACE}
      addresses:
        - ${vlans[$id]}
EOL
done

cat "${NETPLAN_FILE}.tmp"
echo "========================"

# Confirmation
read -p "Do you want to apply these settings? (yes/no): " confirm
if [[ $confirm == "yes" ]]; then
    make_backup "$NETPLAN_FILE"
    mv "${NETPLAN_FILE}.tmp" "$NETPLAN_FILE"
    echo "Configurations have been written to $NETPLAN_FILE. Please review and apply with 'netplan apply'."
else
    echo "Changes not applied."
    rm "${NETPLAN_FILE}.tmp"
    exit 0
fi
echo "========================"